Java tutorial
/* * Copyright (c) 2008-2014 the original author or authors. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package org.cometd.common; import java.io.IOException; import java.io.InputStream; import java.io.Reader; import java.text.ParseException; import java.util.List; import com.fasterxml.jackson.databind.JavaType; import com.fasterxml.jackson.databind.ObjectMapper; import org.cometd.bayeux.Message; public abstract class Jackson2JSONContext<T extends Message.Mutable, I extends T> { private final ObjectMapper objectMapper = new ObjectMapper(); private final JavaType rootArrayType; protected Jackson2JSONContext() { rootArrayType = objectMapper.constructType(rootArrayClass()); } public ObjectMapper getObjectMapper() { return objectMapper; } protected abstract Class<I[]> rootArrayClass(); public T[] parse(InputStream stream) throws ParseException { try { return getObjectMapper().readValue(stream, rootArrayType); } catch (IOException x) { throw (ParseException) new ParseException("", -1).initCause(x); } } public T[] parse(Reader reader) throws ParseException { try { return getObjectMapper().readValue(reader, rootArrayType); } catch (IOException x) { throw (ParseException) new ParseException("", -1).initCause(x); } } public T[] parse(String json) throws ParseException { try { return getObjectMapper().readValue(json, rootArrayType); } catch (IOException x) { throw (ParseException) new ParseException(json, -1).initCause(x); } } public String generate(T message) { try { return getObjectMapper().writeValueAsString(message); } catch (IOException x) { throw new RuntimeException(x); } } public String generate(List<T> messages) { try { Message.Mutable[] mutables = new Message.Mutable[messages.size()]; messages.toArray(mutables); return getObjectMapper().writeValueAsString(mutables); } catch (IOException x) { throw new RuntimeException(x); } } public JSONContext.Parser getParser() { return new ObjectMapperParser(); } public JSONContext.Generator getGenerator() { return new ObjectMapperGenerator(); } private class ObjectMapperParser implements JSONContext.Parser { public <T> T parse(Reader reader, Class<T> type) throws ParseException { try { return getObjectMapper().readValue(reader, type); } catch (IOException x) { throw (ParseException) new ParseException("", -1).initCause(x); } } } private class ObjectMapperGenerator implements JSONContext.Generator { public String generate(Object object) { try { return getObjectMapper().writeValueAsString(object); } catch (IOException x) { throw new RuntimeException(x); } } } }